Blue tints are obtained by laying the picture in a bath composed as follows:
| A.— | Uranium nitrate | 2 grams |
|---|---|---|
| Water | 200 cubic centimeters | |
| B.— | Red prussiate of potash | 2 grams |
| Water | 200 cubic centimeters | |
| C.— | Ammonia-iron-alum | 10 grams |
| Water | 100 cubic centimeters | |
| Pure hydrochloric acid | 15 cubic centimeters |
Immediately before the toning, mix
| Solution A | 200 cubic centimeters |
| Glacial acetic acid | 20 cubic centimeters |
| Solution B | 200 cubic centimeters |
| Solution C | 30 to 40 cubic centimeters |
Brown tints. Use the following solutions: {542}
| A.— | Uranium nitrate | 12 grams |
|---|---|---|
| Water | 1,000 cubic centimeters | |
| B.— | Red prussiate of potash | 9 grams |
| Water | 1,000 cubic centimeters |
And mix immediately before use
| Solution A | 100 cubic centimeters |
| Solution B | 100 cubic centimeters |
| Glacial acetic acid | 10 cubic centimeters |
Pictures toned in this bath are then laid into the following solution:
| Water | 1,500 cubic centimeters |
| Pure hydrochloric acid | 5 cubic centimeters |
| Citric acid | 20 grams |